Rat-hole packer



W. T. WELLS RAT HOLE PACKER Aug. 29, 1933.

Filed Sept. 23, 1952 //v VENTOR) Patented Aug; 29, 1933 srares FATEApplication September 23, 11932 Serial N47). 634,59@

2 (Claims. (Cl. ltdlt) The present invention is an improved rat-hole orliner type packer for use in wells which have,

packer oi the type herein described.

The objects of this invention include:- The provision of a packer forthe uses specified, wherein is provided a central by-pass extending thruthe packing elements, and affording means for fluid passagetherethrough, said packer being a separable structure provided withyieldable means for holding the separable parts apart as the device isrun in through dense drilling mud commonly employed in rotary drilling.

The provision in a rat-hole packer wherein a central by-pass extendingtherethrough is closed by compressive force applied to head and footmembers, one of which is secured to, and the other slidable on, a tubingstring, of a secondary valve controlling a bleeder passage which communicates with said by-pass.

The purposeof said secondary valve is to facilitate the release of thepacker after having been set.

In the structure hereinafter described the first upward movement of thetubing string, before actual lifting strain is applied to pull thepacker, is eifective to open said by pass, and cause a suddenequalization of hydrostatic pressure above and below the packingelement.

Field experience shows that fewer units of weight are recorded on theweight indicator of the derrick rig when the packer is lifted in thismanner.

By breaking the hydraulic lock at the bottom by the use of my bleedervalve, much less strain is imposed on the elevator. This is an importantadvantage of my invention which makes its use of advantage in deep wellswherein long heavy strings of tubing are run in and out thru densedrilling mud. It also makes certain the removal of a packer underextreme pressure conditions and eliminates the necessity of lifting theentire area against the resistance of heavy rotary mud.

In the accompanying drawing, Figure 1 is a vertical cross sectional viewof my packer as it would appearat rest upon the shoulder of the rat-holein open formation before weight of the tubing string, from which it issuspended, had been applied to deform the packing elements.

Figure 2 is a similar view of the same packer, in set position, but hereshown as employed to pack around a well casing shoe, said packer restingon a liner hanger of conventional type.

Figure 3 .is a section of Figure 1 taken on the doted line Ill-HI ofsaid figure.

Figure 4 is a section of Figure 1 taken on the line IV- LV of saidfigure, and

Figure 5 is a sectional view ofa modified de tail.

Referring to the drawing, the numeral 1 indicates the lowermost memberof a tubing string from which my packer is suspended. Tubing l isthreaded at 2 to engage a collar 3. A slip head, member a is slidable ontubing 1, and over collar 3, and is provided with an annular groove 6which the head 4: are compressed as shown in Figure 2.

Groove 6 is closed and passages ll sealed in this position by an annulartongue member 14 integral with collar 3.

A pointed tube 16 provided with perforations 17 is threaded at 18 intothe head a and conducts fluid from the zone below the packer thru achamber 19 in said head to the tubing string l.

A collar 21 secured to tube 16 supports the foot member 13 and said footmember and thehead d are normally held apart as the packer is run in, byan expansion spring 22, one end of which bears against said head, andthe other end against lugs 23, Figure '4, integral withsaid foot member.

Said lugs also serve to align said foot member with tube 16 upon whichit slides.

Foot member 13 is here shown as built upof' a series of laminated sheetsA and B of woven or reinforced material, such as belting, adapted to bedeformed by compression between the head 4 and foot 13 and thereby sealthe well or casing, as the case may be, against passage of fluidtherethrough, as shown in Figure 2.

Here the foot member 13 is shown in deformed position, being compressedby weight of tubing string 1. Said weight is transmitted thru collar 3which bears against groove 6 closing same, and this pressure collapsesspring 22, causing head 4 to contact the upper surface of foot 13, de-

forming the laminated packing A and B and setting the packer. V

In Figure 2, foot member 13 rests on a liner hanger 26 from which issuspended a liner 2'7.

In that type of well shown in Figure 1 said foot member rests on ashoulder 28 of formation.

Operation My packer is run in a well on a tubing string 1 until the footmember 13 encounters an obstruction at the bottom (shoulder 28 or linerhanger 26). As the packer is being lowered thru dense drilling mud orother fluid, spring 22 holds head 4 and foot 13 out of contact, and themud is displaced through by-pass 12 and out between said members.

As soon as foot member 13 is interrupted in its travel, the descendingtubing string moves collar 3 downwardly until tongue 14 closes groove 6in the head 4, and the weight of said tubing string collapses spring 22,bringing head and foot 13 into contact, closing by-pass l2 and deformingthe packing elements AB, and setting the packer.

When it is desired to remove the packer the tubing string is raised, andthe first upward movement thereof lifts collar 3, uncovering ports 8,whereupon hydrostatic pressure in the well zone above the packer passesthru said ports 8, thru passages 11, and thru by-pass 12 to the zonebelow the packer.

.The suddenness of this operation produces an impact of sufficient forceto jar the packer looses. and relieve the elevating rig from unduestrain of hydraulic lock.

This fact has been clearly demonstrated by the weight indicator on thederrick. During early experiments this bleeding of the by-pass wasaccomplished by dropping a go-devil from the top thru the tubing string.

Before this was done a lifting force more than sufiicient to lift thesuspended string but not enough to dislodge the packer was applied tothe tubing string. A reading was taken from the weight indicator dialand recorded.

The bleeder was then opened by droppinga weight, and lifting strainagain applied. The packer and tubing string was then removed with alifting power the maximum of which was much less in amount than that ofthe previously recorded reading.

'In addition to this gauge reading, visual proof was afforded by thefact that at the instant the go-devil struck, the pipe string surgedupward and ofiered no resistance, other than dead weight, to itsremoval.

In Figure 5 I show an elongated form of the slip head 4 in which theports 8 are disposed in helical arrangement therethrough and theirnumber increased, and more room is provided for movement within saidhead of the collar 3.

This structure provides a means for throttling the capacity of the ports8 by positioning the said collar. This makes it possible to equalizepressure above and below the packer, either gradually or suddenly asheretofore described.

Another instance of the advantage of this structure is manifest in theremoval of gas accumulation in the zone below the packer.

While the primary valve (contact between head 4 and foot 13) is closed,collar 3 can be lifted to uncover as many of ports 8 as are required toaccommodate the gas flow and relieve said pressure accumulation.

I claim:-

1. A device of the character disclosed, comprising a pair of sections oftubing joined in an endto-end relation in a manner providing a limiteddegree of relative movement, a packing element, slidable on the lower ofsaid sections, adapted, when deformed, to'seal the space between saidsection and an adjacent wall, said element having a by-pass channeltherethrough, connecting the zones above and below said packing, outsideof and independent of said tubing, a head member secured to said lowersection and slidable with respect to the upper of said sections, havingports therethrough adapted to register with the by-pass channel thrusaid packing element, means, responsive to weight of the upper tubingsection, for actuating said head member to deform said packing elementand close said by-pass, means, responsive to movement of said uppersection for selectively opening and closing said ports while saidby-pass is-closed by said head member, and

means, yieldable to the weight of said upper tubing section, holdingsaid head member and said packing element apart, and said by-pass open,while the device is being raised or lowered.

' 2. A packer of the character disclosed compris- V ing a sectionaltubing string, wherein sections are joined in end-to-end relation byslip-joint struc above said packing element, a closure, associated withthe upper of said tubing sections, adapted to open and close said portswhen said upper section is reciprocated, and an expansion spring urgingsaid head member and said packing element apart and keeping said flowchannel open.

WALTER T. WELLS.

